.TH std::match_results::str 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::match_results::str \- std::match_results::str

.SH Synopsis
   string_type str( size_type n = 0 ) const;  \fI(since C++11)\fP

   Returns a string representing the indicated sub-match.

   If n == 0, a string representing entire matched expression is returned.

   If 0 < n && n < size(), a string representing n^th sub-match is returned.

   if n >= size(), a string representing the unmatched match is returned.

   The call is equivalent to string_type((*this)[n]);

.SH Parameters

   n - integral number specifying which match to return

.SH Return value

   Returns a string representing the specified match or sub match.

.SH Example


// Run this code

 #include <iostream>
 #include <regex>
 #include <string>

 int main()
 {
     std::string target("baaaby");
     std::smatch sm;

     std::regex re1("a(a)*b");
     std::regex_search(target, sm, re1);
     std::cout << "entire match: " << sm.str(0) << '\\n'
               << "submatch #1: " << sm.str(1) << '\\n';

     std::regex re2("a(a*)b");
     std::regex_search(target, sm, re2);
     std::cout << "entire match: " << sm.str(0) << '\\n'
               << "submatch #1: " << sm.str(1) << '\\n';
 }

.SH Output:

 entire match: aaab
 submatch #1: a
 entire match: aaab
 submatch #1: aa

.SH See also

   operator[] returns specified sub-match
              \fI(public member function)\fP
